Skip to main content
Ch. 2 - Graphs of the Trigonometric Functions; Inverse Trigonometric Functions
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601Non è quello che usi tu?Cambia libro di testo
Capitolo 2, Problema 51

In Exercises 43–52, determine the amplitude, period, and phase shift of each function. Then graph one period of the function. y = 2 cos (2πx + 8π)

Guida verificata passo dopo passo
1
Identify the general form of the cosine function: \(y = A \cos(Bx + C)\), where \(A\) is the amplitude, \(B\) affects the period, and \(C\) affects the phase shift.
Find the amplitude by taking the absolute value of \(A\). In this case, \(A = 2\), so the amplitude is \(|2| = 2\).
Calculate the period using the formula \(\text{Period} = \frac{2\pi}{|B|}\). Here, \(B = 2\pi\), so substitute to get \(\text{Period} = \frac{2\pi}{2\pi}\).
Determine the phase shift using the formula \(\text{Phase shift} = -\frac{C}{B}\). Given \(C = 8\pi\) and \(B = 2\pi\), substitute to find the phase shift.
To graph one period of the function, start at the phase shift on the x-axis, then mark points at intervals of \(\frac{\text{Period}}{4}\) to capture key points of the cosine wave (maximum, zero crossing, minimum, zero crossing, maximum). Use the amplitude to determine the y-values at these points.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
4m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Amplitude of a Trigonometric Function

Amplitude is the maximum absolute value of the function's output, representing the height from the midline to the peak of the wave. For functions like y = a cos(bx + c), the amplitude is the absolute value of 'a'. In this example, the amplitude is |2| = 2, indicating the wave oscillates 2 units above and below the midline.
Video consigliato:
Percorso guidato
6:04
Introduction to Trigonometric Functions

Period of a Trigonometric Function

The period is the length of one complete cycle of the wave, calculated as (2π) divided by the absolute value of the coefficient 'b' in y = a cos(bx + c). Here, with b = 2π, the period is 2π / 2π = 1. This means the function repeats every 1 unit along the x-axis.
Video consigliato:
Percorso guidato
5:33
Period of Sine and Cosine Functions

Phase Shift of a Trigonometric Function

Phase shift is the horizontal translation of the graph, found by solving bx + c = 0 for x, giving x = -c/b. It indicates how far the graph shifts left or right from the origin. For y = 2 cos(2πx + 8π), the phase shift is -8π / 2π = -4, meaning the graph shifts 4 units to the left.
Video consigliato: